Of san francisco



Jan. 22, 1929.

C. H. BALMAT FURNACE Filed June 2, 1925 Jan. 22, 1929.

1,699,732 0. H. BALMAT I FURNACE Filed June 2, 1925 2 Sheets-Sheet 2Patented Jan. 22, 1929.

' UNITED I STATES J PATENT OFFICE;

CECIL H. 'BALMAT, or sAN FRANCISCO, GALIFORNTA,ASSEGNOIQVBY miisNEAssren MENTS, T0 STANDARD OIL coMrANYoF CALIFORNIA, or SAN FRANCISCO,CALI- FORNIA, A CORPORATION OF DELAWARE.

summon.

Application filed June 2,

This invention relates to a furnace for burning fuel oils, espec allyheavy fuel 0118,.

and while the furnace may be adapted for it is necessary to effect asuitable atomization of the fuel, to provide the correct quantity ofair, and to maintain the propertemperature during combustion. Theburners which are used in industrial plants for burning heavy oilsare'usually either of a type in which steam, or sometimes air, underhigh pressure is utilized to atomize the oil; or, of a type in which theoil is broken up by mechanical means, either by being forced to issuefrom a small orifice or from the periphery of a rapidly revolving, cup.In domestic installations, steam under high pressureis notavailable;neither is compressed air, and. furthermore, burners using these meansfor atomization are noisy in operation and require exact control,preferably by an expert. Burners using mechanical means for effectingthe pulverizationv of the fuel arc, in general, not very flexible underdomestic conditions-that is, they havespoor ability to change from asmall to a large fire cflicientl Furthermore, they require con siderablecleaning. M Those burners which utilize pressure alone for theatomization of the oil require high pressure pumps and in small sizes,such as would be suitable for domestic use, the orifices are necessarilyso small as to become very easily stopped up, One of the difiiculties inburning oil in a domestic furnace lies in the fact that the shape andproportions of the furnace or dinarily availablearesuch as to require avery short length of flame, that is, extremely rapid combustion;moreover, the usual. furnace will not hold the heat at low burning ratessufficiently to effect proper combustion. In order to burn heavy fueloilssuccessfully in the usual domestic furnace, therefore, it isnecessary to effect the most thorough atomizationof the fuel in order tobring the flame length into the practical limits ime posed by the spaceavailable. pointed out, this thorough necessitates the use ofcomplicated means, V and, in general, is very difficultto effect indomestic installations, These difficulties obtain primarily becauselittle orno attention As just atomization 192 5, SerialNo. 34,364.

has been given to the proper shape and d esign-of the furnace fireboxaudits relation to theburner.

H The general ob ect ofthis invent on is to which the requisitetemperature conditions are always maintained, even for, the smallestproduce a furnace of simple construction in flres, and operating in sucha way that the gases during combustion pass through a rela tivelylongpath; also to provide a construction in which the flame or gas duringCOlIlbLlStiOIliSfiflllSGd to reverberate Within thefirebox, at the sametime providing means for protecting the .burner from direct impingementof the reverberating flame; also to provide means for producing aregenerating eifectwithin the firebox, by directing the reverberated.flame along the same path as the flame issuing from the burner;valsotoprovide meansfor confining the flame more or less totheimmediatevicinity of the firebox; also to provide a furnace ofrelatively small volume constructed entirely of refrac-v tory materialwhich becomes highly heated and radiatesor throwsback a large amount ofheatto the fire; and bythis construction to permit the use of relativelysimple means for atomization, or to increasemateriallyv the ciliciencyand flexibility of burners utilizing more complicated means. 1

A further object of the invention is to provide a construction in whichthe fuel oilis sufficiently heated to enable it to flow freely to theburner tip, and to assist itsatomiza tion, but in which the fuel issufliciently protected from the furnace heat to prevent itsvolatilization before itreaches-the tip oftlie burner. Q i

Further objects of the invention will appearhereinafter. a q

Theinvention consists in the novel parts and combination of parts, to bedescribed hereinafter, all of which contribute to produce an efflcientfurnace. l I

A preferred. embodiment of the invention. is described in the followingspecification, while the broad scope of the invention is pointed out inthe appended claims.

In the drawings: j A Fig. l is a diagrammatic view showing in sideelevation a furnace embodying my invention, the upper port-ion of, thefurnace being broken away.

fire box, taken about on the line 22 of Fig. 1.

Fig. 3 is a cross section taken through the furnace above the fire boxon the line 33 of Fig. 1;. i

Fig. 4 is a vertical section taken through the fire box on the line 4l4of Fig. 3.

Fig. 5 is a vertical section at the side of the fire box wall andshowing a modified embodiment for the face of this wall to 1ncrease theconduction of heat 1nto the furnace wall;

-Fig. 6 is a horizontal section through a portion of the fire box walland showing another embodiment of the idea disclosed in an enlargedscale.

Fig. 7 is a vertical section through the wall of the fire box andshowing a portion of the burner in section, the rest of the burner being"shown in elevation and the connection to it broken away. This view isupon Fig. 8 is a vertical section taken on the line 8-8 of Fig. 7illustrating details of the locking means for holding the fuel pipe inany adjusted position.

Fig. 9 is a longitudinal section illustrating a modified embodiment ofthe burner nozzle.

"Fig. 10 is a front elevation of the burner shown in Fig. 9. r

Fig. 11 is a longitudinal section showing another embodiment of theburner.

1 Fig. 12 is a front elevation ofthe' burner shown in Fig. 11.

Fig. 13 is a plan of the tip of the fuel pipe shown in Fig. 7.

Fig; 14 is a side elevation of the tip shown in Fig. 13.

Fig. 15 is a horizontal section through the fuel pipe tip taken about onthe line 1515 of Fig. 14.

.Thefurnace 1 which is illustrated. is of the upright type, with a firebox 2 at its lower end and a combustion chamber 3 above the fire box.Inapplying my invention to a furnace of this type, I provide means foradmitting an. air blast and fuel at one side of the fire box, and Iconstruct the fire box in such. a way as to effect a reverberation ofthe flame or gases during combustion in a substantially horizontal Iplane so that they are made to flow back to provided with regeneratormeans adjacent the burner which also operates to assist in protectlngthe burner from impingement of the flame.

' air nozzle 5.

In orderto accomplish this, I provide a burner 4 which operates as anair duct or This nozzle 5 is of relatively large diameter and carrieswithin it a fuel pipe 6 which in the present instance is constructed-tocarry a relatively heavy oil fuel. The oil pipe 6 is preferably locatedcentrally in the air nozzle so that it is insulated by the air blastfrom the temperature in the fire box wall 7 in which the burner 4 ismounted; this burner is constructed so that although sufiicient heatreaches the pipe to enable the oil to flow freely in the coldestweather, at the same time it is sufliciently insulated due to theconstruction of the burner that the oil passing through the pipe willnot become vdlatili'zed. The air nozzle 5 preferably has a tapered orconical tip 8, and the tip 9 of the fuel pipe preferably projects afraction of an inch through the orifice of the air nozzle (see Fig. 7).The forward end of the oil pipe may be supportedin a cross bar 10 whichpasses diametrically across the air nozzle. The pipe 6, however, isadjustable through this arm or bar 10. The air blast is preferablyfurnished by a fan or blower 11 which may be driven by an electric motor12. The air is preferablyat a relatively low pressure.

Any suitable means may be employed for controlling the flow. of the airblast to the burner, for example, a valve 13 may be provided which inthe present instance is lo cated between the blower and the burner. Byclosing this valve more or less, the amount of air flowing to the burnermay be nicely regulated. This valve may be of any desired type.

The fuel oil may be supplied through a flexible pipe 14: which admitsthe oil through a valve 15 at the back end of the fuel pipe 6. At itsouter end, the fuel pipe is carried. in a bushing 16 which is screwedinto the back of the air nozzle and suitable means may be provided forlocking the fuel pipe and bushing in any adjusted position. For thispurpose, the bushing 16 may have an extension or neck 17 at its innerend with a longitudinal groove 18 which may receive a set-screw 19 (seeFig. 8).

Referring again to the fire box 2., the wall opposite to the burner isprovided with means, for example a rid go or abutment 22. extending in avertical direction, which is located on the axis of the burner, and thisridge operates to divide the gases during combustion, or the flame, intotwo currents, as indicated by the arrows in Fig. 2; in other words, theinner end of the fire box is constructed with a grooved face 20 at eachside which guides the flame back toward the front of the fire box.

I provide suitable means to prevent this flame from impinging on theburner, and this function is performed by regenerator means in the formof a tunnel 21 between two regenerator walls 23 disposed on oppositesides of the tunnel. Back of each wall 23 is a flue 24 through whichthegases or flames pass; at a point near the nozzle, and on each side ofthe nozzle, the wall of the tire box is provided with curved guide faces25 which bend the flame or gases during combustion toward the back ofthe furnace. In other Words, this end of the fire box is shaped so as todeflect the flame forwardly and over the burner so that it also assiststhe regenerator in protecting the burner from the flame.

When the furnace is in operation, of course the regenerator walls 23become very highly heated, and if any drops of oil fail to be atomizedsufficiently and fall upon the faces of these walls 23, they will beimmediately ignited or will be taken up again by the current of gasespassing these faces. The furnace is preferably provided with meansoperating to confine the gases during combustion more or less to thefire boxes. Any suitable means may be provided for this purpose, but inthe present instance I merely provide the inner face of the furnace wallwith a coping 26 which projects horizontally into the furnace chamberand divides the ire box from the combustion chamber 3 above it. Thiscoping extends further out into the fire box at the end of the fire boxwhich islocated near the burner, so that it extends over the regeneratorwalls 23 and assists in forming the return flues 24.

In starting up a furnace with a heavy fuel oil, it is sometimesnecessary to provide special means for igniting the oil and warming upthe burner. This may be accomplished if desired by throwing someoil-soaked waste into the furnace, or, if desired, a gas con nection 27may be run into the back part of the furnace. If desired, the connection27 may be used after starting the furnace for delivering an additionalsupplyof air, or other connections may be used at] other points in thefurnace for admitting additional air for combustion. The tip 9 may haveany form or construction desired, and steam, air, mechanicahor othermeans may be used to effect the desired atomization of the fuel; Iprefer, however, to utilize a low pressure airblast for atomizing thefuel'a-nd to construct the tip so that it has the features illustratedin Figs. 13 to 15. This tip is produced by swaging out the end of theoil pipe to the shape of a fun-' nel and then flattening it to afan-shaped outline. Between the two sides a narrow slot is left, andthiscapillary space is kept intact during the remaining operations by anysuitable means, but most conveniently by the insertion of a triangle ofthin sheet metal, which iswithdrawn when the Work is finished. The tipis then rolled about a longitudinal axis so that, looking on the end,

the slot becomes circular in form. One of the sides thus is made intothe inner wall or tongue 28, and the other becomes the outer wall and acont-inuation of the pipe. By this operation, the points 29 of theflattened tip arerolled together over the tongue so. that they'meet asat the point 30, in' Fig. 13. In this way, directly over the tongue 28,an air duct 31 is formed through which the air blast flows as indicatedby the arrow in Fig. 13; the effect'is to provide a narrow groovedthroat 32 (see Fig. ,15) into which the oil will pass by capillaryattraction. This-enables the tipto operate effectively although theremay be a very small quantity of, oil arriving at the tip.

In order to increase theheat radiating surface of the furnace wall, Imay provide the interior ofthe fire box with horizontal corrugations 33(see Fig. 5) or I may provide it with corrugations 34 (see Fig. 6),vertically. The form of corrugations shown in Fig. 5 seems to bepreferable,however, because it does not impede or produce eddycurrcntsin-the flame as it passes-along'the side walls of the fire box;at the same time it would produce a very intimatecontact between theflame and the fire box wall, en-

abling the wall to absorb a very consider able quantity of the heat inthe gases or flame. 1

Other types of fuel pipe tips or nozzles are illustrated in Figs. 9 to12. In the form shown in Fig. 9, the end of the fuel duct or fuel pipe35 is bent up and formed into an annular nozzle 36 into which a bushing37 may be screwed from the rear. This bushing 37 carries an air duct 38.The bushing 37 is of slightly smaller diameter than the nozzle 36, sothat a narrow annular space 39 is formed around the bushing which may,if it is small enough, exert capillary attraction on the oil. y

In the type of burneror oil pipe tip shown in Fig.11, the pipe 40 isdrawn down into a tapered end orspear 41 which passes into the center ofan air nozzle 42 to which it is connected. "A passage 43 leads from theinterior of the spear into a conical annular space 44 around the nozzleI2, this space is formed by screwing on the nozzle 4 2 an outer nozzle4510f conical form.

It isevident that in theoperation of this furnace, the construction ofthe fire box is such as to guide the flame or gases during combustion ina relatively long path within the fire box. At the sametime', aregenerator effect is produced, though the burner is protected fromimpingement of the flame.

,The fire-box, of course, may be constructed of fire clay, fire brick,or any other suitable take, and I do not wish to be limited in thepractice of the invention, nor in the claims, to the particularembodiment set forth.

What I claim is 1. In a furnace for burning heavy oils, the combinationof a fire-box, an air-duct mounted in the fire-box wall, a fuel-oil pipeextending longitudinally through the airduct and projecting at its innerend beyond the end of the air-duct, said air-duct being of relativelylarge diameter whereby the fuel pipe within the same is insulated fromthe high ten'iperaturei of the fire-box wall, and regcnerator meanslocated in the fire-box adj acent the burner, said tire-box having meansfor effecting a reverberation of the gases during combustion past theregenerator means.

2. In a furnace for burning heavy oils, the combination of a fire-box,an air-duct mounted in the fire-box wall, a fuel-oil pipe extendinglongitudinally through the air-duct and projecting at its inner endbeyond the end of the air-duct, said air-duct being of relatively largediameter whereby the fuel pipe within the same is insulated from thehigh temperature of the fire-box wall, and regenerator n'ieans locatedin the fire-box adjacent the burner, said fire-box having means foreffecting a reverberation of the gases during combustion past theregenerator means, said fuel pipe being disposed substantially centrallywithin the air duct, whereby the vairblast surrounding the fuel pipeoperates to cool, and insulate the same from the high temperature of thefire-box wall.

3. A furnace for burning heavy fuel oils having a burner constructed tooperate with a low pressure air blast, and operating to atomize oil withthe air blast and direct the same across the firebox of the furnace, acombustion chamber above the fire-bo ,sa-id tire-box having a ridge inits wall opposite the burner to divide the burning gases and effect areverberation thereof by directing the same in currents passing alongthe face of the side walls of the furnace back toward the burner, saidfire-box having means projecting in from the wall above the current ofgases operating to confine the same within the fire-box, a regeneratordevice at each side of the nozzle in a position to become highly heatedby the flame from the burner, and covered tunnels on the outer sides ofthe regenera-tor devices receiving the said currents of gases passingalong the walls of the fire box, and means in the fire-box adjacent theburner for deflecting the currents passing through the tunnels forwardlypast the burner and between the regenerator devices.

4. In a furnace, the combination of a firebox and a combustion chamberabove the fire-box, a nozzle for admitting the fuel, a regencratoradjacent the nozzle with a regenerator-wall on each side of the nozzleand having a return flue on the outerside of each regenerator wall,means for admitting an air blast at the nozzle so as to direct the fuelbetween the regenerator walls, said firebox having means for effecting areverberation of the gases during combustion rear- Wardly through thesaid fines and thereafter forwardly between the regenerator walls.

5. A fire box having means for effecting fire-box having a ridge in itswall opposite the burner to divide the burnin gases and effect areverberation thereof by directing the same in two currents in the samehori zontal plane and passing along the face of the side walls of thefurnace back toward the burner, said fire-box having means projecting infrom the wall above the currents of gases operating to confine the samewithin the firebox, a regenerator device at each side of the nozzle in aposit-ion to becomehighly heated by the flame from the burner, andcovered tunnels on the outer sides of the regenerator devices receivingthe said currents of gases passing along the walls of the fire-box, andmeans in the fire-box adjacent the burner for deflecting the currentspassing through the tunnels forwardly past the burner and between theregenerator devices.

7. A furnace for burning heavy fuel oils having a burner constructed tooperate with a low pressure air-blast and operating to atomize oil withthe air-blast and direct the same across the tire-box of the furnace, acombustion chamber above the fire-box said firebox having a regeneratorwall on each side of the burner, disposed in a substantially verticalplane and extending longitudinally with the axis of the'burner, saidfire-box having covered flues on the outer sides of the regeneratorwalls forming covered tunnels for directing the flame back toward theforward wall of the fire-box, the forward wall of the firebox havingmeans on each side of the burner for de'liectingthe currents passingthrough the said fines, past the burner and between the regen-eratorwalls and toward the rear wall of the furnace.

8. In a furnace for burning heavy fuel oils, the combination of a burnerconstructed to operate with a low pressure air-blast and operating toatomize oil with the air-blast and direct it across the fire-box of thefurnace, a combustion chamber above the fire-box, the back wall of thefire-box operating to divide the current of flame from Wall of thefurnace along the vertical faces the burner into two currents in'thesame horlzontal plane passing toward the front of its side Walls, a pairof regenerator Walls disposed in a substantially vertical plane one oneach side of the burner and extending longitudinally with the axis ofthe burner, said fire-box having a covered flue on the outer side ofeach regenerator Wall forming a tunnel for guiding its correspondingcurrent of flame back to the front wall of the fire-box, the said frontWall ofthe fire-box having means for deflecting the two revervberatedcurrents of flame past the burner and between the said regeneratorWalls.

Signed at San Francisco, Calif. this 21st day of May, 1925.

Y L CECIL H. BALMAT.

